Apache Knowledge Base

AH00558: apache2: Could not reliably determine the server's fully qualified domain name

  1. Create a file in /etc/apache2/conf-available/ for the server causing the error message.
    Example:
    touch dummy.com.conf
  2. Add the following line to the file created above: ServerName yourservername. yourservername can be set to anything you want.
    Example:
    ServerName dummy.com
  3. Then run sudo a2enconf yourservername from a terminal.
    Example:
    sudo a2enconf dummy.com
Source:
askubuntu.com